What counts is what works - but how can we actually tell what works? And what can we do with such knowledge to influence policy and practice? As all parts of the public sector embrace 'evidence' as a means of providing more effective and efficient public services, this book provides a timely and novel contribution to such debates. The authors consider the role of evidence in specific public policy areas (healthcare, education, criminal justice, social care, welfare, housing, transport and urban renewal), using experts in each field to explore the creation, dissemination and use of evidence within each. They consider in particular: How is research evidence of service effectiveness created? How does such evidence shape policy and influence service delivery? What efforts are being made to encourage greater utilisation of evidence in policy and practice? The rich cross-sectoral accounts of the many and diverse activities in each sector provide an insight into the ebb and flow of evidence as guidance to policy and practice. 'What works?' develops perceptive analyses of outstanding problems, and raises challenging agendas for service development and future research. The authors conclude with the all-important question of the implementation of evidence-based practice and lead the way to the reinvigoration of innovative thinking. With its relevance to both cutting-edge practice and research, this book is important reading for a wide range of managers and professionals in different sectors, as well as students and academics studying public policy, public administration, and social policy and management.